Vacuum fuel-feed device.



Patented Mar. 4, 1919.

6D the cup, C,

WEBB JAY,

OF CHICAGO,

ILLINOI VACUUM FUEL-FEED DEVICE.

Specification of Letters Patent.

Patented Mar. 4, 1919.

Application filed April 26, 1918. Serial No. 230,961.

To all MILO/IL it may concern Be it known that l, VVnun JAY, a citizen of the United States, residing at (,hicago, in the county of (00k and the State of Illinois, have invented certain new and useful 1mprovements in Vacuum Fuel-Feed Devices, of which the following is a specification, reference being had to the accompanying drawings, forming a part thereof.

The purpose of this invention is to provide an improved construction in the outlet and inlet passages of a vacuum chamber of a vacuum fuel feed device. It consists in the elements and features of construction shown and described, as indicated in the claims.

In the drawings:

Figure 1 is a detail section of a vacuum fuel feed device of familiar construction, section being made through the several inlet and outlet passages of the vacuum chamber, axially thereof.

Fig. 2 is a detail section of a modified form of atmosphere inlet controlling valve in conjunction with the form of passage shown in Fig. 1.

The drawing shows a familar construction of vacuum fuel feed device in which there is a v cuum chamber, or chamber in which a partial vacuum is induced by a connection with a source of suction, usually the intake manifold of the engine served, and having, a liquid fuel supply connection, an atmos 'ihere inlet and. a connection for discharge into the reserve chamber or reservoir; the atmosphere inlet and the suction connection being \'tll\tt-(OlltlOllflL the valves being operated by a float in the vacuum chamber according to the level of liquid therein. A is the wall of the vacuum chamber, B is the wall of the reserve chamber or reservoir within which the vacuum chamber is suspended according to familiar construction. C is the top cap of the device through which the atmosphere inlet passage and suction connection passage and fuel supply passage are made. D is the suction connection pipe leading to the suction port, d, in a tube, D, which is screwed into the cap, C, from below. E is a tube similarly set having the atmosphere in letmssage, E. F is the suction-controlling valve. G is the atmosphere inlet valve, said valves being connected by the lever system which is indicated generally by the reference letter, H, and which is of familiar construction, operating said valves by means of the float, J, according to the level of liquid in the vacuum chamber. K is the liquid fuel supply pipe through which the, fuel is drawn by suction from a low level main supply tank not. shown. M is a tube set into the cap, C, and having the fuel inlet passage, M. N is a tube having the fuel outlet passage from the vacuum chamber to the reserve chamber or reservoir, B, which passage is controlled at its discharge end by the flap valve, 0.

The characteristic of this invention is the form of the inlet and outlet passages of the vacuum chamber, which passages as shown are of Venturi tube form, that is, comprising two conical portions tapering in opposite directions from a most constricted point or throat, the anterior portion being of a wider angle or more abrupt taper than the posterior portion.

The suction-controlling valve, F, and the atmosphere valve, (l, at the throats or most constricted points of the Venturi tubes, respectively, may be conical or of the so-called needle valve form, of sharper taper than the anterior portion of the Veuturi passage, so as to seat substantially at a line, that is, without breadth of seat. at the throat or narrowest portion of the Venturi tube, the stems, F and G, extending through the Venturi tube for connection with the operating lever system, H. The form of these valves is of some importance because obvi ously the valve should obtain its seat at the narrowest portion of-thc passage which it controls, and should not have an extended seating area around that passage, and this result is effected by employing the tapered or needle valve form described of sharper taper than the anterior portion of the Venturi tube, so that the seating area is minimum. But a ball. valve, G, which may be pushed off its seat and guided back onto it by the tapered Venturi tube will meet the conditions stated and may be conveniently employed, particularly as the atn'iosphere valve.

The atmosphere inlet passage of the Venturi form described has the eflect that a given degree of partial vacuum in the vac- ,uum chamber causes a muclrmore rapid supply of air through the atmosphere inlet when the atmosphere valve is open, than would be obtained through a lain cylindrical passage of the diameter of the constricted throat of the Venturi passage, this result being obtained by virtue of the demonstrated ctl'ecl of a passage of this Venturi form through which a fluid is being moved either by pressure or suction. This is of very considerable importance in the ease of the atmosphere inlet valve in a device of this character. in which a large atmosphere port is objectionable because of the large area which it al'l'ords for station upon the atmosphere valve, imposing heavy duty upon the float which must operate the valve for opening it against this suction, but in which it is very important that the air supply should be atfcrded promptly and rapidly. As stated. a Venturi tube passage afl'ords a prompt and rapid supply of the atmosphere through a relatively small port which may be closed by a valve having a correspondingly small area exposed to the suction for holding it seated ai st the effort. of the float.

The of the Venturi-formed passage for the, suction inlet is similarly to cause a giverg degree of partial vacuum in the source of vacumn to produce a like partial \acuum in the vacuum chamber, A, more quickly than if the Suction port were a mere straight-walled opening.

Likewise, the effect of the Venturi-form of fuel inlet passage is to cause the chamber to fill more rapidly unde a given condition of partial vacuum in said chamber, and the supply pipe line to empty more slowly in the intervals; and the effect of the cnturi form of liquid outlet passage shown at N is likewise to cause more prompt and rapid outflow from the vacuum chamber into the reserve chamber.

1. In a vacuum fuel teed device for internal combustion engines, the vacuum chamher having an atmosphere inlet and a suction connection; a valve controlling the atmosphere inlet, and means for operating said valve according to the level of the liquid in the cl ia'mber, the passage constituting said atmosphere inlet being in the form of a Venturi tube having the more abrupt taper at its outer end.

2. In a construction such as set out in claim 1 foregoing, the valve for closing the atmosphere inlet passage being positioned in the outer tapered portion of the \"enluri tube for seating inwardly, and being of sharper taper than said outer portion of the, Yenluri.

$5. In a vacuum t'uel feed device for internal combustion engines, the vacuum chamher having atmosphere inlet, suction conncclion and fuel suppl \"inlet the passage constituting the fuel supply inlet having its discharge member in the form of a Venturi tube having the more. abrupt taper at its outer end.

4. In a vacuum t'ucl feed device for internal combustion engines. the vacuum chamber having an atmosphere inlet and a suction connection; a valve controlling the suction connection and means for operating lhe valve according to the level of liquid in the chamber; the passage constituting said suction connection being in the form of Venturi tube having the more abrupt taper at lls inncrend.

a. In a vacuum fuel feed device for internal combustion engines, comprising a chamber into which the fuel supply is drawn by suction and from which it is discharged by gravity at substantially atmospheric pressure, and a reserve chamber or reservoir into which said fuel supply is thus discharged, the discharge passage from the lirst mentioned chamber into the second being of Venturi tube form, having the receiving end more widely tapered than the discharge end, and a valve for closing it at the discharge end.

6. In a construction such as set out in claim 4-. foregoing, the valve. for closing the suction connection passage being positioned in the more abruptly tapered portion of the Venturi tube, and being of sharper taper than said portion of said tube.

In testimony whereof. I have hereunto set my hand at (hit-ago, Illinois, this 15th day of April, 1918.

WEBB JAY. 

